## #23 - Physics professor: Some scientists claim that

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Complete Question Explanation

Justify the Conclusion-CE. The correct answer choice is (E)

The physics professor argues that superheated plasma with failed electrical resistance is never a factor in causing ball lightning, because such lightning would emit intense light and rise in the air, which runs contrary to her own observations. You should expect this conclusion from the very first sentence of the stimulus: whenever the author begins by stating what "some people claim," you know that her conclusion would be the exact opposite of their argument.

To justify the professor's conclusion, you need to ensure that the instances of ball lightning that she observed are representative of all instances of such lightning. What if the cases she observed were not caused by superheated plasma but other cases were? To prove her conclusion, all types of lightning must have the same cause.

Answer choice (A): If superheated plasma can only cause ball lightning, the author's conclusion would be weakened. This answer choice does the exact opposite of what is needed and is incorrect.

Answer choice (B): Even if others observed the same phenomena as the professor, this would only strengthen her argument, not provide sufficient proof for it. This answer choice is incorrect.

Answer choice (C): If ball lightning can occur as a result of several different factors, then perhaps superheated plasma played no role in it. Or perhaps it did? Because the effect of this answer choice upon the argument is less than clear, it is incorrect.

Answer choice (D): That superheating gas-like substances causes bright light to be emitted is a given. You cannot justify a conclusion by repeating a premise already relied upon. This answer choice is incorrect.

Answer choice (E): This is the correct answer choice. If all types of ball lightning have the same cause, and the instances observed by the author disprove the notion that superheated plasma played a role in them, then superheated plasma is never a factor in causing ball lightning. Do not shy away from strong language in Justify the Conclusion questions: oftentimes, the correct answer choice must employ strong language in order to prove the conclusion.
Applesaid

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Oh hey, hope someone can help me out with this type of question.

My interpretation of the passage follows like this:

superheated plasma--->ball lightning--->intense light and rise in the air

However because it says that his observed effects (low intensity and horizontal floating) failed the previously stated effects of intense light and rise in the air. He concludes that the cause of superheated plasma is false. (Am I right?)

And then, I am not sure how to further analyze to conclude the correct answer choice (E)...
Ron Gore
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Hi, Apple! Thanks for your question.

This certainly is a complicated question, in part because it includes both causal and conditional reasoning.

The professor starts by presenting the theory of "some scientists," that superheated plasma in which electrical resistance fails is a factor in causing ball lightning. The professor then provides a conditional relationship pertaining to the theory of "some scientists," providing two requirements that must be the case if the scientists are correct:

ball lightning emits intense light

superheated plasma is a factor AND

ball lightning rises in the air

The professor then uses this conditional relationship to draw a conclusion from his own observations of ball lightening. In those instances, the lightning was of low intensity, rather than emitting intense light, and floated horizontally before vanishing, rather than rising in the air.

ball lightning emits intense light

OR superheated plasma is a factor

ball lightning rises in the air

Applying the conditional relationship to her observations, the professor concludes that superheated plasma with failed electrical resistance is never a factor in causing ball lightning.

A weakness in the professor's conclusion is its scope. While the conclusion appears valid regarding the instances observed by the professor, the stimulus provides no reason to think there is only one type of ball lightning, or that the evidence provided by the professor's observations was sufficient to deduce a general rule regarding the causation of all instances of ball lightning.

This is a Justify the Conclusion question, so the correct answer choice, once added to the stimulus, will show the conclusion is valid. Answer choice (E) properly extends the conclusion drawn by the professor from just those instances of ball lightning observed by the professor to all instances of ball lightning. It accomplishes this by providing the fact that "all types of ball lightning have the same cause." If all instances have the same cause, then the professor's conclusion that since superheated plasma in which electrical resistance fails was not the cause of the ball lightning he observed, then superheated plasma in which electrical resistance fails is never the cause of ball lightning.

I hope this helps! Please let me know if I can assist you further.

Thanks!

Ron